npm install --save-dev @apollo/server supertest @types/supertest

import { ApolloServer } from '@apollo/server';
import { typeDefs, resolvers } from './schema';

const testServer = new ApolloServer({ typeDefs, resolvers });

test('returns greeting', async () => {
  const response = await testServer.executeOperation({
    query: 'query SayHelloWorld($name: String) { hello(name: $name) }',
    variables: { name: 'world' },
  });

  // Parse/validation/execution errors surface in `errors`, not thrown
  if (response.body.kind !== 'single') throw new Error('expected single');
  expect(response.body.singleResult.errors).toBeUndefined();
  expect(response.body.singleResult.data?.hello).toBe('Hello world!');
});

const res = await testServer.executeOperation(
  { query: GET_LAUNCH, variables: { id: 1 } },
  {
    contextValue: {
      user: { id: 1, email: 'a@a.a' },
      dataSources: { userAPI, launchAPI },
    },
  },
);

import { startStandaloneServer } from '@apollo/server/standalone';
import request from 'supertest';

let server: ApolloServer;
let url: string;

beforeAll(async () => {
  server = new ApolloServer({ typeDefs, resolvers });
  ({ url } = await startStandaloneServer(server, {
    listen: { port: 0 },   // OS picks port → parallel-test safe
  }));
});

afterAll(async () => {
  await server?.stop();
});

it('says hello over HTTP', async () => {
  const response = await request(url)
    .post('/')
    .send({ query: '{ hello }' });
  expect(response.status).toBe(200);
  expect(response.body.data?.hello).toBeDefined();
});

npm test                    # jest / vitest pick up *.test.ts
npx jest schema.test.ts -t "introspection"

import { ApolloServer } from '@apollo/server';

test('introspection disabled when production', async () => {
  process.env.NODE_ENV = 'production';
  const prodServer = new ApolloServer({
    typeDefs, resolvers,
    introspection: process.env.NODE_ENV !== 'production',
  });
  const resp = await prodServer.executeOperation({
    query: '{ __schema { types { name } } }',
  });
  if (resp.body.kind !== 'single') throw new Error('expected single');
  expect(resp.body.singleResult.errors).toBeDefined();
  expect(resp.body.singleResult.errors?.[0].message).toMatch(/introspection/i);
});

test('hideSchemaDetailsFromClientErrors strips did-you-mean', async () => {
  const server = new ApolloServer({
    typeDefs, resolvers,
    hideSchemaDetailsFromClientErrors: true,
  });
  const resp = await server.executeOperation({
    query: '{ usre { id } }',  // typo
  });
  if (resp.body.kind !== 'single') throw new Error('expected single');
  expect(JSON.stringify(resp.body.singleResult.errors)).not.toMatch(/did you mean/i);
});

test('strict APQ rejects unregistered hash', async () => {
  const server = new ApolloServer({
    typeDefs, resolvers,
    persistedQueries: false,  // turn off auto-register
    plugins: [/* strict-allowlist plugin from manifest */],
  });
  const { url } = await startStandaloneServer(server, { listen: { port: 0 } });

  const resp = await request(url).post('/').send({
    extensions: { persistedQuery: { version: 1, sha256Hash: 'deadbeef'.repeat(8) } },
  });
  expect(resp.body.errors[0].extensions.code).toMatch(/PERSISTED_QUERY/);
});

type ExecuteOperationResult =
  | { body: { kind: 'single'; singleResult: { data?: ...; errors?: ... } } }
  | { body: { kind: 'incremental'; ... } };

# .github/workflows/graphql-tests.yml
name: graphql
on: [pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5
      - uses: actions/setup-node@v4
        with:
          node-version: '20'
      - run: npm ci
      - run: npm test
      - name: Production-config assertions
        env:
          NODE_ENV: production
        run: npx jest tests/production-config/ --forceExit